| Purpose:Pentacam was used to investigate the change rule of the pupil diameter from photopic vision to scotopic vision and the effect of blinking on the dark-adapted pupil diameter.This study will provide some clinical reference for assessing changes of scotopic pupil.Methods:Observational study.A total of 97 subjects(189 eyes)were included,including 71 normal eyes and 118 myopic eyes.Pentacam 70700 instrument and Dino-Lite digital microscope system were used to collect the pupil diameters of non-blinking and blinking eyes.The following information was recorded:(1)Pupil diameters at different time points when photopic vision shifted to scotopic vision;(2)Pupil diameter variations before and after blinking.Repeated measure analysis of variance(ANOVA)and correlation analysis were used to compare the difference of pupil diameters at different time points and the effect of blinking on the pupil diameter.Results:1.Dynamic changes of the pupil diameter in the normal group and myopic group during the transition from photopic vision to scotopic vision in people of different ages:(1)In the normal group,the pupil diameters of all subjects during illumination and darkness for 1–23s were: illumination(3.48±0.81),darkness for 1s(2.88±0.59),darkness for 3s(4.10±0.79),darkness for 5s(4.41±0.82),darkness for 7s(4.61±0.82),darkness for9s(4.73±0.84),darkness for 11s(4.82±0.83),darkness for 13s(4.86±0.83),darkness for15s(4.91±0.83),darkness for 17s(4.96±0.83),darkness for 19s(5.00±0.83),darkness for21s(5.04±0.82),and darkness for 23s(5.06±0.82).There were statistically significant differences in the pupil diameter at different time points(all P < 0.001).That is,in the early stage of dark adaptation,the pupil diameter of the normal group showed a trend of first contracting and then dilating,and the pupil diameter was negatively correlated with age during illumination(r =-0.715,P < 0.001).(2)In the myopic group,the pupil diameters of all subjects during illumination and darkness for 1–23s were: illumination(3.52±0.57),darkness for 1s(2.93±0.47),darkness for 3s(4.27±0.49),darkness for 5s(4.66±0.48),darkness for 7s(4.84±0.49),darkness for9s(4.96±0.51),darkness for 11s(5.04±0.51),darkness for 13s(5.10±0.51),darkness for15s(5.15±0.51),darkness for 17s(5.18±0.54),darkness for 19s(5.20±0.53),darkness for21s(5.24±0.52),and darkness for 23s(5.28±0.51).There were statistically significant differences in the pupil diameter at different time points(all P < 0.001).That is,in the early stage of dark adaptation,the pupil diameter of the myopic group also showed a trend of first contracting and then dilating.(3)When shifting from photopic vision to scotopic vision,the pupil diameter of all subjects was first contracted in the first second.Then,the pupil dilated rapidly.After 5s,the pupil dilation tended to be stable.Note that there was a negative correlation between the pupil diameter variation in the first second and age(r =-0.698,P < 0.001),but no significant correlation with the diopter(r =-0.048,P > 0.05).2.Pupil diameter changes in the normal group and myopic group before and after blinking in people of different ages:(1)The pupil diameter variation before and after blinking in the normal group was0.21±0.12,where those of the juvenile group,youth group,and middle-aged group were0.25±0.08,0.26±0.12,and 0.12±0.08,respectively.The pupil diameter variations of the juvenile group and youth group were higher than that of the middle-aged group,and the difference was statistically significant(P < 0.05),but there was no significant difference in the pupil diameter variations between the juvenile group and youth group(P > 0.05).That is,the effect of blinking on the pupil diameter in the juvenile group and youth group was larger than that in the middle-aged group.(2)The pupil diameter variation before and after blinking in the myopic group was0.22±0.20,where those of the low myopia group,moderate myopia group,and high myopia group were 0.16±0.17,0.24±0.24,and 0.24±0.15,respectively.There was no statistical significance among the three groups(P > 0.05).That is,blinking of subjects with different diopters did not affect the pupil diameter variation.Conclusion:1.In the early stage of dark adaptation,the pupil diameter of all subjects shows a trend of first contracting and then dilating.Moreover,the pupil diameter variation in the first second is negatively correlated with age,but not with the diopter.2.The pupil dilation tended to be stable at after 5s and the measuring time of pupil diameter in dark should be at least 5 seconds after entering the dark environment.3.Blinking causes the pupil to contract in diameter.The effect of blinking on the pupil diameter in the juvenile group and youth group is larger than that in the middle-aged group,and blinking of subjects with different diopters has no correlation with the pupil diameter variation. |
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